Effects of insecticides on Orius spp. in an eggplant field

Abstract

The effectiveness of nine insecticides against Orius spp., an indigenous natural enemy of melon thrips, Thrips palmi Karny, was investigated in an eggplant field. Among the effective insecticides against twenty-eight-spotted ladybird (TSL), metaflumizone did not reduce the density of Orius spp., but indoxacarb reduced it by about half compared with control at 1 week after treatment. Among effective insecticides against two-spotted spider mite (TSM), pyflubumide, milbemectin, and spirotetramat did not reduce the Orius spp. density. Both acetamiprid and dinotefuran were effective against green stink bug (GSB), and emamectin benzoate and flometoquin were effective against melon thrips, reduced the Orius spp. density, but increased to about one-third to half density compared with the control by 2 weeks after treatment. Results show that, for conservation biological control of melon thrips, metaflumizone can be utilized for TSL control, and pyflubumide, milbemectin, and spirotetramat can be utilized for TSM control. Because acetamiprid and dinotefuran for GSB control reduced the Orius spp. density, spraying emamectin benzoate or flometoquin simultaneously is encouraged for the control of melon thrips until the Orius density recovers.